Electronic devices often have one or more integrated circuit (IC) components that perform various functions. Such components can be mounted onto a printed circuit board (PCB) as a way of keeping components in place, as well as to provide electrical and thermal contact to and from the components. One traditional way of installing a device onto the PCB is to have a top-side base plate of the housing face toward the PCB when installed. That is, the top-side base plate can be a generally planar surface on the housing wherein an IC die—usually the main part of the device itself—is mounted inside the housing on the opposite side of the top-side base plate. That is, this installation places the IC die and the top-side base plate essentially onto the PCB in the desired location, which facilitates electrical connection and some amount of heat transfer, to be discussed below. The device can then have pins connected to the IC die by wire bonding, the pins extending through the side of the housing and down onto the PCB. Essentially, the pins can extend toward the plane of the heat transfer surface.
IC dies often create significant heat when used. Because the device itself and/or nearby components can be sensitive to excessive heat, it may be necessary to provide for heat removal from the device. However, the heat conduction through a regular PCB may not be sufficient. Due to this, a “coin” made of copper or other heat conducting layer is sometimes installed in the PCB directly underneath the device to improve the heat conduction and to provide electric connection. However, using coins can add unwanted cost to, and/or can restrict the density of, the circuit design.
Another existing approach involves cutting a hole in the PCB and partially embedding the device therein so that the leads come out exposed on the side(s) of the device. Below such a PCB, a platform can be raised to contact the bottom of the device and serve as a heat sink. That is, this example also involves some form of top-side base plate to which the IC die is mounted (inside the device), and the device is installed so that the top-side base plate is essentially near the surface of the PCB. However, this approach can also add unwanted cost and/or restrict component density.
Another existing approach involves, like the ones above, a packaging in which the top-side base plate on which the IC die is mounted resting onto the PCB. On top of the IC die and inside the packaging of the device, a metal member is positioned that extends through the wall of the housing and forms an exposed, upwardly facing surface. However, this approach also has the disadvantage that the top-side base plate with the IC die are mounted essentially in direct contact with the PCB which as mentioned is usually not a good thermal conductor.